A conventional LARP module employs LARP technology. In this technology, a conversion element that is arranged at a distance from a radiation source and that has, or consists of, a phosphor is irradiated by excitation radiation, e.g. an excitation beam or pump beam or pump laser beam, e.g. by the excitation beam of a laser diode. The excitation radiation is at least partly absorbed by the phosphor and at least partly converted into conversion radiation or into conversion light, the wavelengths of which and hence the spectral properties and/or color of which are determined by the conversion properties of the phosphor. In the case of the down conversion, the excitation radiation of the radiation source is converted by the irradiated phosphor into conversion radiation with longer wavelengths than the excitation radiation. By way of example, this allows blue excitation radiation, e.g. blue laser light, to be converted into red and/or green and/or yellow conversion radiation with the aid of the conversion element. In the case of a partial conversion, white used light arises, for example, from a superposition of non-converted blue excitation light and yellow conversion light.
The LARP module has a block-shaped housing, a circular cylindrical, socket-shaped holding section for a conversion element extending away from said housing. Here, the holding section encompasses the beam path between a radiation source and the conversion element which is arranged approximately at the end side of a free end section of the holding section. Here, a nominal position for the laser spot on the phosphor lies on the longitudinal axis of the holding section and is consequently provided in the center of the phosphor. Due to manufacturing processes and on account of tolerances, it is possible that the excitation radiation does not impinge on the phosphor at the theoretical nominal position. As a result of this, an offset arises between the laser spot and the nominal position. However, the optical elements disposed downstream of the LARP module must be positioned as accurately as possible in respect of the actually occurring position of the laser spot.